From 748aa38378887006da6e9bc5e7330dbc6a3fc692 Mon Sep 17 00:00:00 2001
From: Erik Johnston <erik@matrix.org>
Date: Thu, 15 Aug 2019 12:02:18 +0100
Subject: [PATCH 1/2] Remove logging for #5407 and update comments

---
 synapse/handlers/sync.py | 22 +++++-----------------
 1 file changed, 5 insertions(+), 17 deletions(-)

diff --git a/synapse/handlers/sync.py b/synapse/handlers/sync.py
index 98da2318a0..ef7f2ca980 100644
--- a/synapse/handlers/sync.py
+++ b/synapse/handlers/sync.py
@@ -786,9 +786,8 @@ class SyncHandler(object):
                         batch.events[0].event_id, state_filter=state_filter
                     )
                 else:
-                    # Its not clear how we get here, but empirically we do
-                    # (#5407). Logging has been added elsewhere to try and
-                    # figure out where this state comes from.
+                    # We can get here if the user has ignored the senders of all
+                    # the recent events.
                     state_at_timeline_start = yield self.get_state_at(
                         room_id, stream_position=now_token, state_filter=state_filter
                     )
@@ -1771,20 +1770,9 @@ class SyncHandler(object):
             newly_joined_room=newly_joined,
         )
 
-        if not batch and batch.limited:
-            # This resulted in #5407, which is weird, so lets log! We do it
-            # here as we have the maximum amount of information.
-            user_id = sync_result_builder.sync_config.user.to_string()
-            logger.info(
-                "Issue #5407: Found limited batch with no events. user %s, room %s,"
-                " sync_config %s, newly_joined %s, events %s, batch %s.",
-                user_id,
-                room_id,
-                sync_config,
-                newly_joined,
-                events,
-                batch,
-            )
+        # Note: `batch` can be both empty and limited here in the case where
+        # `_load_filtered_recents` can't find any events the user should see
+        # (e.g. due to having ignored the sender of the last 50 events).
 
         if newly_joined:
             # debug for https://github.com/matrix-org/synapse/issues/4422

From ebba15ee7f00f2aad2a6a2a3b2e2b4810f83282c Mon Sep 17 00:00:00 2001
From: Erik Johnston <erik@matrix.org>
Date: Fri, 16 Aug 2019 13:29:41 +0100
Subject: [PATCH 2/2] Newsfile

---
 changelog.d/5860.misc | 1 +
 1 file changed, 1 insertion(+)
 create mode 100644 changelog.d/5860.misc

diff --git a/changelog.d/5860.misc b/changelog.d/5860.misc
new file mode 100644
index 0000000000..f9960b17b4
--- /dev/null
+++ b/changelog.d/5860.misc
@@ -0,0 +1 @@
+Remove log line for debugging issue #5407.